Vending machines are found in many commercial establishments and other facilities such as schools, hospitals, sports stadiums, etc. They dispense drinks and food as well as other items such as stamps, toys, etc. Vending machines may accept payment in a variety of forms, including coins, paper money, credit cards, debit cards, and smart cards.
A potential drawback to using vending machines is that failed transactions, i.e., where the customer pays money and does not get the item requested, may not be remedied by the machine. In some instances, the customer may be able to cancel the transaction and receive a refund from the machine. However, if the failed transaction is due to a mechanical problem, for instance, the requested product getting jammed in the vending machine so that it doesn't drop so the customer can reach it, the customer may not be able to receive either a refund or the desired product. In these cases, the customer either has to wait for a repair service to refund the money or simply forfeit the money spent on the failed transaction. In other cases, a customer may try to jostle the machine in order to shake loose either the requested product or the money, which may result in injury either to the customer or the machine or both. Clearly, it would be desirable for vending machines to be equipped to recognize successful transactions and remedy failed transactions.
U.S. Pat. No. 6,384,402 to Hair, III et al. discloses a system to ensure a vending machine motor continues to operate either until a product is vended or a predetermined time period has elapsed. When the product is vended or dropped to where the customer can reach it, the product interrupts an optical beam in a vend space and a change in light intensity is detected, indicating the product was successfully vended. If no signal indicating the product was vended is received, the spirals holding a product will continue to be turned in an attempt to vend a product that was loaded improperly. If the spirals are rotated and a time interval has elapsed, the selector panel gives the customer the option of having his or her money refunded or to select another product.
U.S. Patent Application Publication Number 2002/0107610 to Kaehler et al. discloses a system and method for vending promotional products along with requested products. A detector within the vending machine detects when the promotional product is vended, either by scanning a code on a product or detecting an RF or magnetic tag placed on the promotional product.
The prior art discussed above relies on either the generation of electromagnetic energy or an additional tag placed on the product. It is an object of this invention to provide a sensor and method to determine whether a requested product has been successfully vended that does not require electromagnetic energy nor additional tagging of the product.